Amazon Payments Overview

Amazon Payments allows your customers to make purchases using their Amazon account, and most importantly, never have their payment information enter your server.

When the customer clicks the Pay With Amazon button it will either ask them to log into Amazon or if they're already logged in it will offer them all the payment options their Amazon account has.

This includes all credit cards and shipping addresses, as well as allowing them to create new ones. When the customer clicks the final purchase button the transaction takes place on the Amazon servers without the end user ever leaving your own site.

A general overview of the setup is that

You'll create a Seller account with Amazon

They'll give you a set of keys

You put them into your EDD settings

Profit!

There are different keys for Live and Sandbox, and there's also a mechanism for creating Test Users on Amazon. It's strongly recommended that you do your testing using a Test User you create on Amazon, it keeps your live personal data out of a potentially unstable test environment.